The present application is directed to an improved labyrinth seal design, and more specifically to a labyrinth seal design which hybridizes known straight through seal designs and known staggered seal designs.
Air flow management machines such as fans, turbines, and compressors typically have rotating air seals which separate areas of high fluid pressure and low fluid pressure within the machine. As a result of the rotation, it is not possible to create a perfect seal which prevents 100% of the leakage which could occur between the high pressure area and the low pressure area. The path which the fluid travels when it leaks from the high pressure area to the low pressure area is referred to as the “leakage flow path.”
In order to reduce the amount of fluid which can flow across the leakage flow path, two types of seals have been used in the prior art. The first type of seal uses a straight leakage flow path and is referred to as a straight through seal. The straight leakage flow path has a large amount of leakage relative to other types of seals. However, it is easy to assemble and is constructed out of significantly simpler and cheaper components than other known seals.
The second type of seal used in the prior art is a staggered seal. The staggered seal creates a flow path which is significantly more restricted than the flow path of a straight through seal. The staggered seal uses a series of fins on the static element and a series of fins on the rotating element within the seal. The fins alternate, with each fin from the rotating element being adjacent to two fins from the static element. This forces the leakage flow path to travel a more complex, winding, pathway and results in a decrease in pressure leakage between the high pressure area and the low pressure area, relative to the straight-through design, due to the leakage flow path being throttled.
The staggered seal design is significantly more complicated to construct, as the fins must be arranged in the correct pattern and have a tight tolerance. The staggered seal additionally uses more expensive components and a greater quantity of components. These two features combined result in the staggered seal assembly costing significantly more to manufacture and assemble than other less complicated seal designs.